The present invention relates to improvements in spacers for use in multiple-pane windows, and more particularly to improvements in so-called connectors or plugs which serve to couple the neighboring ends of tubular components of such spacers to each other.
It is well known to assemble the spacer or spacers of a multiple-pane window from a single length or from several lengths of a tubular stock whose end portions are placed substantially end to end and are coupled to each other by plugs extending into the interior of such end portions. Reference may be had, for example, to FIGS. 8 and 9 of U.S. Pat. No. 4,261,145 to Brocking which discloses a method of making tubular spacers as well as one type of a plug which can connect two neighboring end portions of a tubular spacer to each other. As a rule, one also resorts to a sealing compound in order to prevent the penetration of atmospheric air into the space which is surrounded by the assembled spacer and is disposed between the neigbhoring window panes. Moreover, the spacer normally contains a suitable desiccant to absorb moisture and to thus prevent premature fogging of the inner sides of the window panes. The plug of the patented sealer has a circumferentially complete rib fitting between the end faces of the end portions which are being joined by the plug, and the dimensions of the circumferentially complete rib are selected in such a way that its peripheral surface is flush with the external surfaces of the adjacent tubular components. This is supposed to ensure predictable contact between the rib and the entire end faces of the corresponding tubular components of the spacer.
A drawback of the patented sealer is that reliable sealing of the butt joint between the neighboring tubular components presents many problems. As a rule, the sealing compound is a rather tough mass of very high viscosity which cannot be readily forced into narrow clearances between the rib and the adjacent end faces of the tubular components. Therefore, the narrow clearances cannot be properly sealed and they invariably establish paths for the inflow of moist atmospheric air which shortens the useful life of the product. Manufacturing tolerances also contribute to the lack of adequate sealing and to premature fogging of the inner sides of the adjacent window panes.
Attempts to overcome the just discussed problems in connection with adequate sealing of joints between the tubular components of the spacer include the making of a spacer which is inwardly adjacent to the edge faces of the adjacent panes, i.e., which is somewhat smaller than the panes so as to provide therearound a circumferentially complete groove for the introduction of a sealing compound all the way around the spacer. Such proposal reduces the likelihood of premature fogging of the panes but does not constitute a highly satisfactory solution for several reasons. First of all, the joint between the end faces of two neighboring tubular components of the spacer remains unsealed and, secondly, the utilization of a relatively small spacer reduces the effective dimensions of the multiple-pane window. Therefore, such solution can be resorted to only when the groove into which the marginal portions of a multiple-pane window are to be fitted is sufficiently deep to conceal the spacer and the sealing compound therearound.
Another drawback of presently known spacers, and especially of the plugs which are used to join pairs of tubular components of such spacers, is that they cannot meet certain other requirements which are expected from an efficient plug. Thus, the plugs must contribute significantly to the stability of the spacer, they must prevent angular displacements of the coupled-together tubular components relative to each other, and they must offer a pronounced resistance to bending and/or other deformation of the joints. Moreover, unavoidable machining or manufacturing tolerances should not adversely affect the tightness and/or appearance of the joints.